RSA Key Pair Generator vs Bcrypt Hash Generator
A detailed comparison of features, privacy, and developer experience.
Last reviewed: 2026-05-17
Executive Summary
RSA is an asymmetric encryption and signing algorithm, two related keys, one public, one private. Bcrypt is a one-way password hash, irreversible by design, deliberately slow to resist brute force. They solve completely different problems and aren't substitutes for each other.
RSA Key Pair Generator
Generate RSA 2048 or 4096-bit key pairs in your browser via Web Crypto API. Supports RSA-OAEP and RSA-PSS, exports PEM, with SHA-256 fingerprint and downloads.
Try RSA Key Pair Generator →Bcrypt Hash Generator
Create strong Bcrypt hashes for passwords with adjustable salt rounds. Includes a verification utility to test strings against existing stored hashes.
Try Bcrypt Hash Generator →Editor's Verdict
If you're storing user passwords, you want Bcrypt (or Argon2). If you're signing a JWT, encrypting a session payload, or setting up TLS, you want RSA, or, increasingly, Ed25519 or ECDSA. The two algorithms live at different layers of the stack: RSA handles confidentiality and authenticity in transit, Bcrypt handles the at-rest problem of "how do we store a secret we never want back in plaintext." Mixing them up, using RSA to "encrypt" passwords, for example, is a classic vulnerability.
What we ran
We minted a 2048-bit RSA pair and a cost-12 bcrypt hash of `MySecurePass123!` on this site. The PEM decrypts with the matching private key; the bcrypt string does not decrypt at all, verify re-hashes the candidate. They are not substitutes.
🗝️When to use RSA Key Pair Generator
- Signing JWTs, certificates, or release artifacts
- Encrypting small payloads with a known recipient public key
- Key exchange in older TLS / SSH
🔐When to use Bcrypt Hash Generator
- Storing user passwords in a database
- Hashing API key check-values
- Any case where you need to verify a secret without storing it
| Feature | RSA Key Pair Generator | Bcrypt Hash Generator |
|---|---|---|
| Type | Asymmetric encryption + signing | Password hash |
| Reversible | Yes, with private key | No (one-way) |
| Key count | 2 (public + private) | 0 (just a salt) |
| Output size | Same as modulus (2048-4096 bits) | 60 chars |
| Speed | Slow for crypto ops | Intentionally slow (work factor) |
| Tuneable hardness | Via key size | Via cost / rounds |
| Replaced by modern alt | Often Ed25519 / ECDSA | Often Argon2id |
| Use in TLS | Yes | No |
| Use for passwords | No (anti-pattern) | Yes |
Key Takeaways
- Different jobs entirely: RSA = asymmetric encryption + signing; bcrypt = one-way password hashing.
- RSA is reversible with the right key; bcrypt is intentionally one-way (verifying = re-hashing the candidate).
- RSA-2048 is the minimum for new keys in 2026; prefer ED25519 for signing where supported.
- Bcrypt cost factor 12+ is current OWASP minimum; Argon2id is the preferred new default.
- Storing user passwords with RSA encryption is a textbook anti-pattern, always use a slow KDF (bcrypt/Argon2id).
Common Mistakes
- Using RSA to 'encrypt' passwords for database storage, defeats the purpose; password hashes are not meant to be reversed.
- Setting bcrypt cost factor below 10 in 2026, too fast against modern GPUs.
- Generating RSA-1024 keys, broken since the early 2010s; use 2048-bit minimum or move to ED25519.
- Reusing one RSA key pair across signing and encryption, best practice is separate keys per purpose.
Frequently Asked Questions
Can I use RSA to hash passwords?+
No. RSA is reversible by design, using it for passwords would mean you can also decrypt them, which is exactly what password hashing is meant to prevent.
Is RSA still safe in 2026?+
At 2048 bits it's borderline; 3072 or 4096 is recommended for new keys. For new projects, Ed25519 (signing) or X25519 (key exchange) are usually a better default.
Should I migrate from Bcrypt to Argon2?+
Bcrypt is still fine for most apps, but Argon2id is the OWASP-recommended default for new systems because it's memory-hard, which makes GPU/ASIC attacks much harder.
Can I store the Bcrypt cost in the hash?+
Yes, Bcrypt hashes include the cost factor and salt as a prefix, so you can verify any old hash even after raising the cost for new users.
How we tested this
We evaluated both RSA Key Pair Generator and Bcrypt Hash Generator in real developer workflows to build this comparison. Our assessment covers feature parity, privacy posture, developer experience, and ecosystem maturity.
Why these tools are worth your time
Privacy-respecting picks
We prefer tools that run locally or are explicit about what they send to the cloud.
Daily-driver tested
Recommendations come from real developer workflows, not marketing pages.
No vendor lock-in advice
We surface the trade-offs so you can switch later without rewriting your stack.